puberty

Puberty is the period of physical and sexual maturation that leads to reproductive capability. It results from hormonal changes that coordinate growth, development, and secondary sexual characteristics, and it is influenced by genetics, nutrition, and overall health.

In most individuals, puberty begins in early adolescence. Girls typically start between ages 8 and 13, and boys between 9 and 14, with wide individual variation. Precocious puberty is the onset before these ranges, while delayed puberty involves absence of signs after an expected age.

The process is driven by the hypothalamic-pituitary-gonadal axis: the hypothalamus releases gonadotropin-releasing hormone (GnRH), prompting the pituitary to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH stimulate the gonads to produce sex steroids—estrogen and progesterone in girls, and testosterone in boys—triggering development.

Typical sequence of physical changes differs by sex. In girls, breast development (thelarche) is usually the first sign, followed by growth of pubic hair, a growth spurt, and hip widening; menarche, the first menstrual period, typically occurs about 2 to 4 years after the start of puberty. In boys, testicular enlargement precedes penis growth, followed by pubic hair, a growth spurt, voice deepening, and gradual facial and body hair.

Across sexes, acne, changes in skin and oil production, body odor, and changes in body composition are common. Hormonal fluctuations can influence mood, energy, sleep, and sexual thoughts, and individuals may experience heightened independence and social sensitivity.

Health considerations include adequate nutrition, regular physical activity, sufficient sleep, and good hygiene. If puberty does not begin by about age 13 in girls or 14 in boys, or if there is no progression for several years, medical evaluation may be warranted to assess possible endocrine or genetic conditions.